Vehicles, such as motor vehicles, are ubiquitous in daily life. Vehicles are continuously improved with consideration for the safety of the driver and passengers. One cause of accidents is failure to maintain the vehicle position on the roadway. For example, if a driver travels onto the shoulder or berm of the roadway, loss of control of the vehicle can result in an accident. Various factors can lead to a vehicle's traveling off the road including inattention by the driver to the position of the vehicle, and poor visibility due to weather, which prevents the driver from identifying lane and roadside signs. In fact, poor visibility due to heavy precipitation can prevent a driver from knowing where the interface of the roadway and the berm of the road are located. For example, in heavy snow, the painted lines delineating the interface of the paved roadway and the berm of the roadway can be completely covered by precipitation, and the driver has no visual indication of whether the vehicle is safely on the road, perilously close to the edge of the roadway, or even completely off the roadway.
Certain high-end vehicles are equipped with a camera-based system to assist the driver in maintaining the vehicle in a particular lane. The camera is mounted in the windscreen and is used to observe the lane markings. Based on feedback from the camera, the position of the car is determined relative to the edges of the roadway. If the vehicle strays out of the lane, a warning indication is provided. This system is unidirectional, and experiences performance degradation in adverse weather (e.g., snow, heavy rain) due to the limitations of resolution of the camera.
Maintaining the relative position of a vehicle or a group of vehicles with respect to the road signs/markings is also necessary to enable new intelligent transportation applications, such as vehicle convoys (or platoons) in which a group of cars are automatically operated and “drive” together as a single unit to improve overall traffic conditions, safety and easy congestion. In grouped or platooned operations of vehicles, the vehicles are clustered together in groups (e.g., 20 vehicles). The spacing between vehicles within a platoon is comparatively short, and the spacing between platoons of vehicles is comparatively long. The platoon mode of operation is conceived as a way of expanding the envelope of capacity and safety that can be achieved by vehicles. However, the limitations of drivers' ability to perceive changes in vehicle spacing, relative motion, and acceleration and their limited speed and precision of response ensure that lane capacity cannot generally exceed 2200 vehicles per hour under manual control. A smart system is needed to provide faster and more precise response than human drivers are capable of providing and the system is not influenced by fatigue or other human shortcomings. The system should be able to keep the groups of vehicles in lane and keeps a good spacing between vehicles.
What is needed, therefore, is a system for guiding vehicles and drivers that addresses at least the shortcomings of known systems described above.